The QTR-L-1A reflectance sensor incorporates a right-angle infrared LED and a right-angle phototransistor in an inexpensive, tiny 0.35″ × 0.3″ module that can be mounted almost anywhere and is great for edge detection and line following.
The reflectance measurement is output as an analog voltage.
This sensor is sold in packs of two units.
When the future is dazzlingly-bright, this ultra-high-range luminosity sensor will help you measure it. The TSL2591 luminosity sensor is an advanced digital light sensor, ideal for use in a wide range of light situations. Compared to low cost CdS cells, this sensor is more precise, allowing for exact lux calculations and can be configured for different gain/timing ranges to detect light ranges from 188 uLux up to 88,000 Lux on the fly.
This reflectance sensor module is designed specifically for use with the Balboa 32U4 balancing robot. It features five IR LED/phototransistor pairs that are great for identifying changes in reflectance on the ground directly underneath the Balboa (like detecting or following a black line on a white background). The sensor array offers dimmable brightness control, and each sensor provides an independent output that can be measured with a digital I/O.